1. Field of the Invention
The present invention relates to a novel polyurethane and elastic polyurethane fiber and a polyesterpolycarbonate diol used for the same.
2. Description of the Related Art
Known polyurethanes are polyester-, polyether- and polycarbonate-based ones. Japanese Patent Application Laid-open Nos. 101496/1973 and 22817/1987 disclose a polyurethane derived from 3-methyl-1,5-pentanediol and a dicarboxylic acid and one from a polyester diol or polycarbonate diol obtained from 2-methyl-1,8-octanediol, respectively.
Japanese Patent Application Laid-open No. 33382/1990 discloses a polyester diol utilizing 2-methyl-1,8-octanediol and a polycarbonate diol utilizing 2-methyl-1,8-octanediol or 3-methyl-1,5-pentanediol and also a polyurethane utilizing a mixture of the polyester diol and the polycarbonate diol as a starting material polymer diol. This polyurethane however cannot be formed into an elastic fiber exhibiting good elastic recovery characteristics at low temperatures.
Japanese Patent Application Laid-open No. 173117/1985 discloses an elastic fiber obtained from a polyurethane utilizing a polyester diol from hexamethylene glycol or 1,10-decanediol. This fiber, utilizing this long-chain diol having no branches, does not have sufficent elastic recovery property.
Japanese Patent Application Laid-open No. 713/1972, U.S. Pat. No. 3,097,192 and Japanese Patent Application Laid-open No. 97617/1988 disclose an elastic fiber of a polyurethane utilizing a polyester diol derived from 2,2,4- or 2,4,4-trimethylhexanediol and adipic acid, one of a polyurethane utilizing a polyester diol from 2,5-hexanediol or 2,2-dimethyl-1,3-propanediol and one of a polyurethane utilizing a polyester diol from (2,2-dimethyl-1,3-propane dodecanedioate) glycol, respectively. The use of these polyesterdiols however fail in providing the obtained fibers with high thermal resistance, elastic recovery and resistance to cold.
Japanese Patent Application Laid-open No. 190717/1989 discloses an elastic fiber of a polyurethane utilizing a polycarbonate diol from 1,6-hexanediol or 1,5-pentanediol. This fiber however is not satisfactory in the elongation.
Japanese Patent Application Laid-open No. 132858/1989 discloses a melt-blown nonwoven fabric of a polyurethane utilizing a polyester diol from 3-methyl-1,5-penetanediol.
An object of the present invention is to provide an elastic polyurethane fiber being excellent in all of resistance to chlorine, water and mildew, thermal resistance and resistance to cold, as well as having high elongation.
Another object of the present invention is to provide an elastic polyurethane fiber having low tensile stress in the low tensile strain region and high tensile stress in the high tensile strain region.